On certain aircraft such as commercial airliners, tankers, airlifters, and transport aircraft, aircraft engines are typically mounted in nacelles that extend from pylons under the wing or that are mounted to the fuselage of the aircraft. In many aircraft, the leading edge of the engine nacelle is positioned forward of the wing leading edge. At high angles of attack, the engine nacelle sheds a wake. For aircraft where the engine nacelles are mounted in close proximity to the wing, the nacelle wake may flow over the wing leading edge and along the upper wing surface. Although the nacelle wake can be aerodynamically favorable under certain flight conditions, at high angles of attack close to the stalling angle where maximum lift is typically achieved, the nacelle wake can cause flow separation along the upper surface of the wing. Such flow separation may result in a reduction in the amount of lift that is producible by the wing in comparison to what might be achievable absent the nacelle wake.
Aircraft manufacturers have addressed the above-described flow separation phenomenon by installing various vortex-generating devices such as strakes (sometimes referred to as “chines”) on the outer surface of the engine nacelle. The strake is typically mounted on a side of the engine nacelle and is sized and positioned to control the separation of the nacelle wake by generating a vortex that interacts beneficially with the wing upper surface boundary layer in order to reduce flow separation.